NEW YORK, N.Y. — Serena Williams’ big lead in the U.S. Open final suddenly was gone.

Her serve was shaky. Her hard-hitting opponent, Victoria Azarenka, was presenting problems, and so was the gusting wind. A couple of foot-fault calls added to the angst.

As a jittery Williams headed to the sideline after dropping a set for the first time in the tournament, she chucked her racket, which ricocheted onto the court.

When play resumed, in the crucible of a third set, Williams put aside everything and did what she does best: She came through in the clutch to win a major match. Facing her only test of the past two weeks, the No. 1-seeded Williams overcame No. 2 Azarenka 7-5, 6-7 (6), 6-1 on Sunday for her 17th Grand Slam championship.

“When you’re always trying to write history, or join history in my case, maybe you just get a little more nervous than you should. I also think it’s kind of cool, because it means that it means a lot to you. It means a lot to me, this trophy,” Williams said, pointing her right hand at her fifth silver cup from the U.S. Open, “and every single trophy that I have.”